If you had just read my initial post (#3) you could have saved yourself all this effort. I can see from your blurry photo that the reverse side of your coin has no upset rim. In the minting process, the blank goes through the Upsetting Mill where the rim is formed for both sides at the same time before it becomes a planchet and enters the coining chamber. Therefore, your coin is not a Uniface Mint Error. It is post-mint damage (PMD), plain and simple. Chris
The problem you have is that it is nearly impossible for the mint to strike a coin with one die and some very specific and unlikely events would need to occur if it was another type of error. However, there have been many examples posted on CT of coins that have had one side ground off. Until you figure out how to get better pics there isn't much you can do to prove its not a damaged coin. When you said it weighed 3 grams, it sounds like your scale only weighs to the nearest gram. Assuming it's calibrated, that means it could weigh as low as 2.5 and and you would still see 3 on the readout
THIS is why I love Coin chats. It's real life folks just being folks with real life coin questions, Not some stuffy coin magazine with name dropping everywhere. Thank folks for being real!